1. Field of the Invention
This invention relates to a machine for the mechanical removal of ice from surfaces such as driveways, sidewalks and parking lots.
2. Description of Prior Art
In winter snow provides a key element for skiing, tobogganing, sledding and other winter sports. It also provides a hazard for both foot and vehicular traffic. A multitude of devices have been used for the removal of snow, from the lowly shovel and broom to the large plows used for clearing highways. All but the largest and most powerful of these are ineffective for the efficient removal of ice or hard-packed snow.
Heavy vehicular or foot traffic packs the snow and forms ice and concurrently, by its mere presence, prevents the utilization of snow removal means. The daily warming and cooling cycle tends to melt and refreeze the packed snow and to complete the transformation to solid ice.
Manual removal of this ice and packed snow is a tedious and arduous task and becomes impractical when the area to be cleaned is large. Labor costs for large commerical areas such as parking lots are prohibitive.
Chemical removal also has its disadvantages. Ordinary rock salt is ineffective below 10.degree. F. (-12.degree. C.). While calcium chloride works at lower temperatures, the quantities of either rock salt or calcium chloride required to effectively remove any substantial deposit of ice often adversely effects surrounding areas. Heavy use of such chemicals kills grass and other plants. The residues are often tracked indoors and stain the shoes and clothing of those traversing the icy area. Environmentalists have expressed concern in recent years over the monumental quantities of ice removing chemicals which are finding their way into and damaging the environment.
The ideal solution would seem to be a powered mechanical device which can effectively and safely remove the ice. Most prior art devices are designed for snow removal and are totally ineffective at removing ice or hard-packed snow. All but the most powerful snow blowers have about the same effect on ice that they would have on bare pavement.
A number of patents have been granted on devices which appear to be converted lawn mowers. See U.S. Pat. Nos. 2,863,162; 2,983,057; 2,984,919; 3,775,878. All of these devices function primarily as snow blowers. Except for some which have dependent sweeping attachments, it is not necessary that they contact the snow to function. The blades and the appendages thereto create a suction which lifts the snow and blows it in the desired direction.
In the use of these devices for ice removal one finds that the functional parts, usually attached to a rotating blade or disc, must maintain continuous contact with the ice being removed. Because of the length of the arms required to get the blowing action, the portions contacting the ice are too far from the center of moment and require more power than the average lawn mower motor can deliver. If one uses a motor which is powerful enough the high speed attained at the end of the blades which contact the ice create a real danger. A piece of ice or a foreign object embedded in the ice, if hit, will be hurled away from the machine and create a safety hazard for bystanders and the operator. Also with the long center of moment, unless the machine is extremely heavy, it will be impossible to control. The machine has a tendency to turn itself rather than remove the ice.